JPH02208325A - Heat-resistant polymer molding and its production - Google Patents

Abstract

PURPOSE:To obtain the title molding improved in heat resistance and dimensional stability by irradiating a molding of block or graft copolymer of a polyester with a polysiloxane with a radiation to thereby crosslink at least part of the polysiloxane. CONSTITUTION:A molding of a thickness <= about 200mum, comprising a block or graft copolymer of 99-70wt.% polyester component (e.g. polyethylene terephthalate) with 1-30wt.% polysiloxane component having structural units of the formula (wherein R1-2 are each a 10C or lower alkyl, a cycloalkyl, an aryl or an aralkyl), is irradiated with a radiation of an accelerating voltage of 10-10000kV at a dose of 3-100Mrad and an irradiation temperature of 30-150 deg.C to crosslink at least part of the polysiloxane component.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a polyester polymer molded article with improved heat resistance and dimensional stability, and a method for producing the same.

(Prior Art) Polyesters such as polyethylene terephthalate and polybutylene terephthalate and various copolyesters containing these as main components have high melting points, high crystallinity, and good mechanical properties, so they are used as fibers.

It is well known that it is used in many fields as molded products such as films and containers. However, in recent years, with the development of the electric/electronic equipment industry, the automobile industry, the aircraft industry, etc., there has been a demand for materials with better heat resistance and dimensional stability.

One of the effective means for improving the heat resistance and dimensional stability of polyester molded articles is a method of crosslinking polyester, as described below.

(2) A compound having a reactive group such as isocyanate, epoxy, or methylol is blended with polyester, and these groups are reacted with the hydroxyl group or carboxyl group at the end of the polyester to cause crosslinking. ■Introduce an unsaturated group (double bond) into the molecule in advance, or mix a compound with an unsaturated group, and at any stage after molding, use heat, light, catalyst, etc. Additional weight is added due to radiation, etc. (Published by Kobunshi Kankai: “Adhesion” Vol. 31, pp. 538-548, Vol. 32, pp. 11-20, Vol. 32, pp. 6
Pages 1-69.

-6 Special Publication No. 61-57850 Publication No. 61-57851, Publication No. 61-5785
Publication No. 2.

Special Publication No. 62-43459. ) However, when the above-mentioned methods ① and ② are adopted.

Thermoplastic polyesters that are useful as fibers and films and have high melting points (softening points) and crystallinity have the following problems.

That is, in the case of ■, generally isocyanate epoxy,
Compounds with groups such as methylol (crosslinking agents) are added when polyester is melt-molded, but these groups are highly reactive, so when processing them into fibers, films, etc., polymerization occurs due to the high molding temperature. This results in gelation or difficulty in fluidizing, which significantly reduces moldability. Also,
It makes it difficult to stretch, which is an important step in the production of fibers and films. Even if a compound having an unsaturated group (2) is introduced or blended into polyester in advance, the unsaturated group is removed at this stage of polycondensation because the polyester is produced (polycondensation) at a high temperature of 250°C or higher. Addition polymerization of the groups may occur, or polymerization may occur due to the elevated molding temperature, resulting in the same phenomenon as in case (2) above.

To avoid such problems, it is possible to adopt a solution polycondensation method or a solution molding method that can be carried out at low temperatures, but problems such as complicating the process and increasing manufacturing costs arise.

(Problems to be Solved by the Invention) In reality, the method that utilizes intermolecular crosslinking as described above can only be applied to polyesters with low melting points, and is useful for polyesters that are useful as fibers, films, and other molded products. The reality is that it cannot be applied to polyesters that have a high melting point and are highly crystalline.

Therefore, the object of the present invention is to provide a high-melting point, highly crystalline polyester molded product with improved heat resistance and two-dimensional stability, and a method for easily producing the molded product. be.

(Another Means to Solve the Problem) As a result of various studies in order to obtain a polyester molded product with a high melting point and high crystallinity that has improved heat resistance and one-dimensional stability, the inventors found that a polyester component and a polysiloxane component By irradiating a molded article made of a block or graft copolymer with a polyester and crosslinking at least a portion of the polysiloxane component, the polysiloxane component can withstand the high temperatures during polyester polycondensation, and is relatively easily irradiated with radiation. It was discovered that a molded article meeting the above purpose can be obtained with good productivity by carrying out a crosslinking reaction, leading to the present invention.

That is, the gist of the present invention is as follows.

(1) A heat-resistant polymer molded article consisting of a block or graft copolymer of a polyester component and a polysiloxane component, characterized in that at least a portion of the polysiloxane component is crosslinked.

(2) A heat-resistant polymer molded article comprising a block or graft copolymer of a polyester component and a polysiloxane component, which is irradiated with radiation to crosslink at least a portion of the polysiloxane component. Manufacturing method.

Two aspects of the present invention will be described in detail below.

In the present invention, the polyester of the "polyester component" means a polyester that can be melt-polymerized and melt-molded,
Its polymerization components include terephthalic acid, isophthalic acid, adipic acid, glutaric acid, azelaic acid, sebacic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid,
Dicarboxylic acid components such as diphenylsulfonedicarboxylic acid, ethylene glycol, diethylene glycol, polyethylene glycol, trimethylene glycol, propylene glycol, 1,4-butanediol, 5-bentanediol, 1,6-hexanediol, neopentyl glycol, xylene glycol, Len glycol.

Cyclohexane dimetatool Gos(β-hydroxyethoxyphenyl)propane, glycol components such as bis(β-hydroxyethoxyphenyl)sulfone, ε-hydroxycaproic acid, β-hydroxyethoxybenzoic acid,
It is obtained by appropriately combining a hydroxycarboxylic acid component such as hydroxybenzoic acid, and in some cases a small amount of a component having three or more functional groups such as trimellitic acid, trimesic acid, pyromellitic acid, trimethylolpropane, and pentaerythritol. It is something. Preferred specific polyesters include polyethylene terephthalate, polybutylene terephthalate, poly-1,4-cyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalate, poly-p-ethyleneoxyhenzoate, and polyesters containing these as main components. It will be done. These are polyesters with relatively high melting points and high crystallinity, and the purpose of the present invention can be particularly utilized.

Next, the polysiloxane of the "polysiloxane component" in the present invention refers to the following formula (1) (however, in formula 2, R, , R2
represents an alkyl group, a cycloalkyl group, an aralkyl group or an aralkyl group having 10 or less carbon atoms. ) is a general term for polymers having a structural unit represented by .

The polymer constituting the molded article of the present invention is a copolymer of the above-mentioned polyester component and polysiloxane component in the form of a block or graft.

These can be produced by adding a polysiloxane component having one or two ester-forming functional groups at the end of the molecule at any stage during the production of polyester. Here, examples of ester-forming functional groups in the polysiloxane component include monofunctional groups such as hydroxyl groups, carboxyl groups, and alkoxycarbonyl groups, and difunctional groups such as epoxy groups. is preferred.

The ratio of the polyester component to the polysiloxane component is 99-70:1-30 by weight. More preferably 98~
A ratio of 80:2 to 20 is preferable in terms of moldability (processability) and crosslinking effect due to radiation irradiation.

The polymer molded article of the present invention only needs to have a structure in which at least a part of the polysiloxane component is crosslinked, and it is not necessarily necessary to crosslink to an insoluble and infusible state so that the polymer has a network structure. . In other words, if at least a portion of the polysiloxane component of the polymer that makes up the film or fiber is crosslinked.

The molded product obtained has good heat resistance and dimensional stability.

The polymer molded article of the present invention can be easily produced by a method of irradiating a molded article made of a block or graft copolymer of a polyester component and a polysiloxane component with radiation.

Examples of radiation include electron beams, alpha rays, gamma rays, etc. 7 Especially, electron beams are preferably used.

The irradiation dose of these radiations is 3 to 100 Mrad.
Particularly preferred is 3 to 80 Mrad. If the irradiation dose is too large, the physical properties of the molded product may deteriorate, which is not preferable. Also, especially when using an electron beam.

Since the depth that the electron beam reaches increases linearly in proportion to the accelerating voltage, it is preferable to adjust the accelerating voltage according to the thickness and thickness of the molded product. The voltage is preferably between 10 and 10,000 KV, preferably between 50 and 5,000 KV. The temperature during irradiation varies depending on the glass transition temperature of the polymer constituting the molded product, but it is best to carry out the irradiation in the range from about 20°C lower than the glass transition temperature to about 60°C higher than the glass transition temperature (especially (For thin or thin items such as films and fibers, be careful not to heat them too high.) Practical temperatures are 30-150°C. The higher the temperature, the shorter the time required for irradiation, but if the temperature is too high, dimensional changes may occur in the molded product before crosslinking has sufficiently progressed, or crystallization may proceed too much, which is not preferable.

Irradiation can be performed in air, in an inert gas such as nitrogen or argon, or in vacuum, but it is practical to perform it in air.

(Example) The present invention will be explained in more detail below with reference to Examples.

Examples 1 and 2 and Comparative Example 1 Both oligomers of bis(β-hydroxyethyl) terephthalate obtained by esterifying terephthalic acid and ethylene glycol (number average degree of polymerization 5) were 93 parts by weight, and the number average molecular weight was 4,000. 7 parts by weight of polydimethylsiloxane having a hydroxyl group at the end and 2 parts of antimony trioxide dissolved in ethylene glycol per mole of terephthalic acid component.
X10-' moles were charged into a batch reactor for polyester polycondensation.

Next, while maintaining the internal temperature at 275° C., the pressure was reduced from normal pressure to a maximum reduced pressure of 0.1 Torr over 0.5 hours, and a polycondensation reaction was carried out under this maximum reduced pressure for 3 hours.

The almost white polyester chips obtained were fed to an extruder type melt extruder and heated to a lip width of 200°C at 280°C.
The extruded molten film was extruded through a T-die with a lip spacing of 0.8 mm and a lip spacing of 0.8 n, and the extruded molten film was cooled and solidified using a casting roller kept at 20° C. to obtain an unstretched film. Next, using a tenter-type simultaneous biaxial stretching device, it was stretched to 3.1 times in length and width at 95°C, and then heat-treated at 235°C with a relaxation rate of 3% in both length and width, and then trimmed to a length of 20 m/width. m
A stretched film having a thickness of 10 μm and a width of 300 fins was obtained.

There were no cutting problems in these film forming and stretching operations, and the operability was good. Moreover, the stretched film showed good appearance.

Next, the obtained stretched film was irradiated at a temperature of 120°C.
An electron beam was irradiated with an accelerating voltage of 750 KV (absorbed dose per second was I Mrad).

Examples 3 and 4 and Comparative Example 2 Polydimethylsiloxane 7 having a number average molecular weight of 3,000 and an epoxy group at one end was used as the polysiloxane component.
A graft copolymer was produced in the same manner as in Example 1 except that parts by weight were used, a stretched film was produced, and the film was irradiated with an electron beam.

Comparative Examples 3 to 5 Stretched films were produced in the same manner as in Example 1 using polyethylene terephthalate homopolymer and irradiated with electron beams.

Table 1 shows the relationship between the structure of the polymer on each side, the irradiation dose, and the dry heat shrinkage rate of the film (processed at 180° C. for 5 minutes). Note that the MD force direction is the longitudinal direction of the film.

TD force direction The transverse direction of the film is shown.

Table 1 (Effects of the Invention) According to the present invention, a polyester polymer molded article having excellent heat resistance and good one-dimensional stability is provided.

Furthermore, according to the method of the present invention, the above-mentioned molded product can be obtained with high productivity.

Claims (2)

[Claims] (1) A heat-resistant polymer molded article consisting of a block or graft copolymer of a polyester component and a polysiloxane component, characterized in that at least a portion of the polysiloxane component is crosslinked. (2) A heat-resistant polymer molded article comprising a block or graft copolymer of a polyester component and a polysiloxane component, which is irradiated with radiation to crosslink at least a portion of the polysiloxane component. Manufacturing method.